This invention relates to an apparatus for cleaning a surface submerged within a liquid. In particular, the invention relates to an apparatus for automatically cleaning swimming pools.
According to the invention there is provided a cleaning apparatus for automatically cleaning a surface submerged in a liquid, the apparatus including a cleaning head having a peripheral region releasably engageable with the surface to be cleaned; two suction passages in suction communication with the head through communication openings therein; and means for automatically transferring liquid flow through the passages from the head alternately and repeatedly from one of the passages to the other.
The suction passages may be linear and may be defined by a rigid material. The passages may have a suitable constant cross-sectional area and may be of a suitable length, dependent on the suction pressure applied to the passages, such that the liquid flowing through either of the passages has sufficient kinetic energy so that when the flow of liquid is transferred to the other passage, sufficient energy is transferred to the apparatus to displace it along the surface to be cleaned. Thus, the means for transferring the liquid flow may be adapted to suddenly halt the flow of liquid through one passage when transferring the liquid flow. By this means, an impulsive force is applied to the apparatus due to the kinetic energy of the liquid flowing in the passage. Further, due to the inertia of the liquid in the passage to which flow is transferred, the suction pressure in the head is decreased when the flow of the liquid is transferred, thereby decreasing the frictional engagement between the head and the surface and allowing the apparatus to be displaced. When the liquid flow increases to its maximum value, the suction pressure increases resulting in the head gripping the surface.
Conveniently, the passages may have the same length. The cleaning head may have a mouth, the region of the head defining the mouth being the peripheral region of the head referred to earlier. This peripheral region may be planar so that the apparatus is particularly suitable for cleaning planar surfaces. With such a planar peripheral region, the axes of the suction passages may be located parallel to each other at an acute angle, preferably of 45.degree., to the plane of the peripheral region. The passages may be oriented in any suitable fashion with respect to the plane of the peripheral region. For example, the axes of the suction passages may be located in a plane perpendicular to the plane of the peripheral region; or alternatively, the passages may be located adjacent each other in a plane which intersects the plane of the peripheral region of the cleaning head at the same angle as the angle between the axes of the passges and the plane of the peripheral region.
The means for automatically transferring the liquid flow from one passage to the other may comprise a flapper valve that is pivotally mounted about a pivotal axis to be sealingly displaceable against valve seats located at the communication openings. This valve may be adapted so that liquid flow from the head into one of the passages tends to displace the valve into sealing engagement with the valve seat of that passage, simultaneously opening the communication opening between the other passage and the head. The pivotal axis may be located either parallel to or at an acute angle to the plane of the peripheral region. In other words, if the head is seated on a horizontal surface the valve will be pivotable in either a vertical or a horizontal plane. In order to assist in displacing the apparatus, one or both of the valve seats may be disposed so that when it is struck by the valve, the apparatus experiences a net force that has a component parallel to the plane of the peripheral region, which reinforces the force exerted on the apparatus due to the kinetic energy of the fluid flowing in its respective passage.
In order to cater for irregularities in the surface to be cleaned, to cater for curved transition zones between adjacent planar surface sections, and to assist in the cleaning action, the apparatus may have a sealing flange of a flexible material about the mouth of the cleaning head. This flange may be rotatably secured to the head. As the suction grip of the head on the surface is increased by such a flange, a relief opening may be provided in the head. Further, the surface of the flange which engages the surface to be cleaned may have an abrasive lining or a brush to assist in cleaning the said surface.
The suction passages may be defined by two tubes, or by a tube having an internal partition. The free ends of the passages will be connectable to a flexible hose by means of which a suction pressure may be applied to the apparatus. These free ends of the passages that are remote from the head may have a common suction inlet having a swivelling coupling that is connectable to the flexible hose.
A regulator valve may also be provided for regulating the suction pressure.
The center of gravity of the apparatus may be located close to the cleaning head. The apparatus may have a buoyancy member to decrease the effective weight of the apparatus in the liquid. The buoyancy member may be disposed on the opposite side to the peripheral region of the head, so that when the apparatus falls through the liquid onto the surface it is correctly oriented for the peripheral region to seat on the surface.
The apparatus may further have means to turn itself when it climbs a vertical wall, the surface of which is being cleaned, to prevent the head breaking the surface of the liquid. Accordingly, the apparatus may include a displaceable ballast member which is automatically displaced due to the action of gravity away from the cleaning head when the peripheral region of the cleaning head is vertically oriented and the apparatus is tilted over a predetermined degree, and which automatically returns to its original position closer to the cleaning head when the peripheral region is horizontally oriented. The ballast member may be a massy ball that is housed in a V-shaped housing disposed with its apex towards the cleaning head.
The cleaning apparatus may be partly or entirely of a mouldable synthetic plastics material. For example, the cleaning head and the valve may be moulded from polyurethane or the like.
The apparatus may be particularly adapted to clean the walls and the floors of the swimming pools. The suction pressure may then be exerted by a conventional pump utilized with the swimming pool, the water sucked through the apparatus being cleaned by the associated filter of the swimming pool.